Push-to-talk, also known as press-to-transmit, is a method of conversing on half-duplex communication lines using a momentary button to switch from voice reception mode to transmit mode. Push-to-talk, or push-to-talk over cellular, may be provided over a handset communication network as a feature similar to walkie-talkie. A handset may be a mobile phone, a wireless communication device, a pager, a personal digital assistant, a portable computer, a tablet computer, a laptop computer, a digital camera, a digital music player, a digital calculator, an electronic key fob for keyless entry, a media player, or an inventory control device.
A typical push-to-talk connection connects rapidly. In some deployments, a push-to-talk connection may typically be established less than one second after activation of the momentary button. One significant advantage of push-to-talk is allowing a single person to reach an active talk group at a button press, thus users no longer need to make several calls to coordinate with a group. Push-to-talk calls are half duplex communications—while one person speaks, the other(s) listen. Traditional mobile phone networks and devices utilize full-duplex communications, allowing customers to call other persons on a mobile or land-line network and be able to simultaneously talk and hear the other party. Full-duplex communications require a connection to be started by dialing a phone number and the other party answering the call, and the connection remains active until either party ends the call or the connection is dropped due to signal loss or a network outage. Full-duplex communications typically do not allow for casual transmissions to be sent to other parties on the network without first dialing them up, as is provided by two-way radios. Full-duplex operation on mobile phone networks is made possible by using separate frequencies for transmission and reception. Some handset communication providers offer mobile push-to-talk service via functionality for individual half-duplex transmissions that are sent to another party on the system without needing an existing connection to be already established. Since such communications are half-duplex, utilizing a single frequency, only one user can transmit by push-to-talk at a time, and the other party is unable to transmit until the transmitting user un-keys their push-to-talk button.